Patent attributes
An electric actuator comprised of an electric motor and a wave gear speed reducer connected to the electric motor efficiently air-cools the electric motor and a wave generator of the speed reducer and obviates the need for increasing the axial length of the actuator. The wave generator has a plurality of holes penetrating in the axial direction, the holes being arranged with intervals provided in the circumferential direction. A partitioning portion between the holes constitutes a vane portion which blows air in the axial direction. An internal space wherein a coil of the electric motor is disposed is in communication with an internal space of the speed reducer, and the vane portion blows air into the internal space of the electric motor. An air cooling passage is formed in a stator of the electric motor such that air flows into the air cooling passage when the vane portion blows air.